NM_001127222.2:c.6714_6719dupACGGGC

Variant names:

• chr19-13208816-A-AGCCCGT
• rs1042488847
• NM_001127222.2:c.6714_6719dupACGGGC

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PM4

The NM_001127222.2(CACNA1A):​c.6714_6719dupACGGGC​(p.Ala2240_Arg2241insArgAla) variant causes a disruptive inframe insertion change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. A2240A) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 31)
• Consequence: CACNA1A NM_001127222.2 disruptive_inframe_insertion
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.33
• Publications: 0 publications found

Genes affected

CACNA1A (HGNC:1388): (calcium voltage-gated channel subunit alpha1 A) Voltage-dependent calcium channels mediate the entry of calcium ions into excitable cells, and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, and gene expression. Calcium channels are multisubunit complexes composed of alpha-1, beta, alpha-2/delta, and gamma subunits. The channel activity is directed by the pore-forming alpha-1 subunit, whereas, the others act as auxiliary subunits regulating this activity. The distinctive properties of the calcium channel types are related primarily to the expression of a variety of alpha-1 isoforms, alpha-1A, B, C, D, E, and S. This gene encodes the alpha-1A subunit, which is predominantly expressed in neuronal tissue. Mutations in this gene are associated with 2 neurologic disorders, familial hemiplegic migraine and episodic ataxia 2. This gene also exhibits polymorphic variation due to (CAG)n-repeats. Multiple transcript variants encoding different isoforms have been found for this gene. In one set of transcript variants, the (CAG)n-repeats occur in the 3' UTR, and are not associated with any disease. But in another set of variants, an insertion extends the coding region to include the (CAG)n-repeats which encode a polyglutamine tract. Expansion of the (CAG)n-repeats from the normal 4-18 to 21-33 in the coding region is associated with spinocerebellar ataxia 6. [provided by RefSeq, Jul 2016]

CACNA1A Gene-Disease associations (from GenCC):

• episodic ataxia type 2

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• undetermined early-onset epileptic encephalopathy

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, Illumina
• developmental and epileptic encephalopathy, 42

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• migraine, familial hemiplegic, 1

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• spinocerebellar ataxia type 6

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Orphanet
• benign paroxysmal torticollis of infancy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial or sporadic hemiplegic migraine

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Lennox-Gastaut syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000300728 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Nonframeshift variant in NON repetitive region in NM_001127222.2.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001127222.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CACNA1A	NM_001127222.2	MANE Select	c.6714_6719dupACGGGC	p.Ala2240_Arg2241insArgAla	disruptive_inframe_insertion	Exon 46 of 47	NP_001120694.1
	CACNA1A	NM_001127221.2	MANE Plus Clinical	c.6717_6722dupACGGGC	p.Ala2241_Arg2242insArgAla	disruptive_inframe_insertion	Exon 46 of 47	NP_001120693.1
	CACNA1A	NM_023035.3		c.6732_6737dupACGGGC	p.Ala2246_Arg2247insArgAla	disruptive_inframe_insertion	Exon 47 of 48	NP_075461.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CACNA1A	ENST00000360228.11	TSL:1 MANE Select	c.6714_6719dupACGGGC	p.Ala2240_Arg2241insArgAla	disruptive_inframe_insertion	Exon 46 of 47	ENSP00000353362.5
	CACNA1A	ENST00000638009.2	TSL:1 MANE Plus Clinical	c.6717_6722dupACGGGC	p.Ala2241_Arg2242insArgAla	disruptive_inframe_insertion	Exon 46 of 47	ENSP00000489913.1
	CACNA1A	ENST00000638029.1	TSL:5	c.6732_6737dupACGGGC	p.Ala2246_Arg2247insArgAla	disruptive_inframe_insertion	Exon 47 of 48	ENSP00000489829.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 36

GnomAD4 genome Cov.: 31

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Episodic ataxia type 2;C4310716:Developmental and epileptic encephalopathy, 42 Uncertain:1

Aug 24, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant, c.6717_6722dup, results in the insertion of 2 amino acid(s) of the CACNA1A protein (p.Ala2241_Arg2242dup), but otherwise preserves the integrity of the reading frame. This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individual(s) with CACNA1A-related conditions (internal data). ClinVar contains an entry for this variant (Variation ID: 653666). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

not provided Uncertain:1

Apr 19, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In-frame insertion of 2 amino acids in a non-repeat region; Has not been previously published as pathogenic or benign to our knowledge

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		5.3

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1042488847; hg19: chr19-13319630;